No Chaos Emeralds? Seriously? I'm out.
Well, idk if it is possible but it would be cool if it were added to the world generation in specific places.
That makes me suggest this :
There are three strongholds (which leads to the end), in each of them you will find two chaos emeralds [one in the library, one in the portal room].
The last chaos emerald is found in the end (in the very center of the main island).
As there will be only seven chaos emeralds, each one gives a massive boost of 128 EU/t in the mystical energy extractor.
If all seven are in a mystical energy extractor, a special event will occur, which is the change of the mystical generator to a special beacon,it would generate 2048 EU/t) and gives potion effects to everyone in a area of 65x511x65 [X,Y,Z] (Regeneration, mining speed, resistance, strength, speed).